Surge type vacuum pump



July 3, 1951 E. M. HADLEY SURGE TYPE VACUUM PUMP Filed June 24, 1948 iili! i-A "air!!! II 5) H/S ATTORNEYS. a, Knee/1; FOSTER & HARE/5 HARRY Patented July 3, 1951 UNITED SATES ATENT OFFICE 11 Claims.

This invention relates to improvements in vacuum pumps and more particularly to improvements in vacuum pumps of the rotary type.

Vacuum pumps of the rotary type in use at the present time generally include a housing which provides a chamber and a rotor adapted to be rotated upon a shaft in said chamber. The pump chamber is provided with an intake orifice and a mechanically valved exhaust orifice which is adapted to permit the passage of exhausted air when the pressure within the pump chamber has been built up by the action of the rotor beyond certain predetermined limits. Such pumps, while relatively eiiicient, are not the most effective means of inducing a vacuum in a closed vessel because considerable back pressure is caused by the utilization of the mechanical valve mechanism at the exhaust outlet.

Diffusion type vacuum pumps are provided which are more effective in inducing a vacuum in a closed vessel than rotary vacuum pumps of the prior art type. However, diffusion type pumps necessarily must be utilized in conjunction with a boiler adapted to produce high tem perature vapors and a cooling system adapted to circulate cooling fluid about the jacket of the pump in order to permit the pump to function at maximum efficiency. Therefore, a considerable period of time must elapse before diifusion type vacuum pumps can be placed in operation. In addition, vacuum pumps of the diffusion type are apt to be exceedingly complex in structure and must be utilized under carefully calculated conditions.

It is, therefore, an object of my invention to provide a rotary type vacuum pump which has embodied therein a pump chamber having an un-valved exhaust orifice communicating directly with the atmosphere. By eliminating the mechanical valve construction of prior art rotary pumps, the efficiency of a pump constructed in accordance with my invention is rendered considerably greater since deleterious back pressure effects are avoided.

It is another object of my invention to provide a rotary type vacuum pump which embodies a rotor having incorporated thereupon a gate structure which is adapted to serve as a valve member to prevent back flow from the chamber of. the pump through the intake orifice thereof. gate of a pump constructed in accordance with my invention thus supplants the mechanical valve arrangements of prior art rotary pumps and is a more efficient expedient since back pressures within the pump chamber are eliminated The l and since the intake orifice is positively sealed from communication with the pump chamber and with the exhaust orifice outlet therefrom.

Another object of my inventionis the provision of a rotary type vacuum pump which has embodied therein surge passage means adapted to cooperate with the gate structure of the rotor incorporated in the pump which is adapted to receive a surge of fluid directed therethrough by the gate structure of the rotor and to'convey the surge of fluid and air embodied or entrained therein into the pump chamber where the entrained air is released from the fluid and discharged through the exhaust orifice.

It is an additional object of my invention to provide a vacuum pump of the rotary type which has embodied therein a rotor incorporating a plurality of gates adapted to cooperate with a surge passage and a fluid embodied in the pump chamber to provide a substantially constant ex haustion of air from a vessel with which the vacuum pump is associated.

A further object of my invention is the provision of a vacuum pump of the rotary type which has associated with the pump chamber a plurality of surge passages arranged at the sides of the chamber and adapted to cooperate with a rotor having a gate embodied therein to intermittently close off the entryports to said passages to permit the exhaustion of air from a vessel with which the pump is associated.

Another object of my invention is the provision of a vacuum pump which is adapted to create a vacuum within a sealed vessel within a few moments initiating the actuation of said pump.

Another object of my invention is the provision of a rotary vacuum pump which may be effectively utilized in a wide variety of installations and which need not be limited to the specific task of exhausting vessels. For instance, a vacuum pump constructed in accordance with my invention may be installed in a refrigeration system to serve in the place of the conventional compressor unit.

An additional object of my invention is the provision of a rotary vacuum pump which is simple in construction and consists of a small number of component parts which may be readily and easily manufactured.

Other objects and advantages of my invention will be apparent from the following specification and the accompanying drawing which is for the purpose of illustration only and in which:

Fig. 1 is a vertical sectional view of a rotary vacuum pump constructed in accordance with my invention having embodied therein a rotor having one gate and a chamber having associated therewith one surge passage;

Fig. 2 is a transverse sectional view of a rotary vacuum pump constructed in accordance with my invention and incorporating a rotor having two gates embodied therein;

Fig. 3 is a transverse sectional view of an alternative embodiment of my invention which consists of airotary vacuum pump having a rotor incorporating one gate and a pump chamber associated with two surge passages; and

Fig. 4 is a perspective view showing the construction of a rotor incorporating one gate adapted to be utilized in a rotary type vacuum pumpconstruction in accordance with my invention.

Referring to the drawings, I show a rotary vacuum pump In which includes a housing II adapted to provide a pump chamber I2. A plurality of appropriately formed feet or supports I? are adapted to support the housing I I in a predetermined position upon a surface It on which it is located.

Disposed at one side of the pump chamber I2 and adapted to communicate therewith through the medium of an entry port I5 and an exit port It is a surge passage IT which is so positioned with regard to the transverse axis indicated as AA in Fig; 1 that end thereof adjacent the entry port I5 lies above the transverse axis of the pump and the other end thereof adjacent the exit port It lies below the transverse axis AA of the pump. Although the passage I1 is shown as a tube I8 lying beyond the confines of the housing H, it is, of course, conceivable that the tube I8 be incorporated within the housing H and the passage IT is thus shown outside thehousing for the purpose of clarity in description of the struc-- ture and function of a rotary type vacuum pump constructed in accordance with my invention.

Since the tube I8, which provides the passage I! having an entry port I5 and an exit port It in communication with the pump chamber I2, is disposed obliquely with reference to the transverse axis AA of the pump I D, it is obvious that the entry port I5 lies on a. plane above that on which the exit port It is disposed. Formed in one side of the tube I8 which constitutes the passage I'T adjacent the entry port I5 to said passage is an intake orifice I!) which is adapted to be placed in communication with a vessel to be exhausted, not shown, by suitable tubes or similar expedients, not shown.

The pump housing I I is generally polygonal in conformation and includes a substantially frustoconical top wall 2| which is joined to a substantially frusto-conical bottom wall 22' through the medium of an annular side wall 23. The entry port I5 and the exit port it are formed in the side wall 23 of the pump housing I I and the tube I'8- which constitutes the passage I! may be affixed in any desired manner, such as by welding, to the-sidewall. The transverse axis AA of the pump bisects the side wall 23 of the pump housing I I and the entry port I5 is disposed substantially above the transverse axis AA while the exit port I6 is disposed substantially below the" transverseaxis AA. The top wall 2 I isprovided with an annular opening 25 which constitutes an exhaust orifice 26 which may be, but is not necessarily so, attached to an exhaust pipe 2''! for the distributionof exhausted air to atmosphere.

The substantially frusto-conical bottom wall 22 of the pump housing I I is provided with a centrally located opening 29'which' has juxtaposed thereto an upwardly projecting, cylindrical sleeve 31 which extends into the pump chamber I2 and lies below the annular opening formed in the top wall 2|. The upwardly projecting, cylindrical sleeve SI may be formed integrally with the housing but, in the present embodiment, is shown as a separately formed element which may be welded, or otherwise suitably affixed, to the interior of the bottom wall 22. about the region of the centrally located opening 29. Secured, as by means of welding, to the underside of the bottom wall 22 about the edge of the centrally located opening 29 is a bearing cage 32 which is adapted to providea housing for a bearing 33 in which is journalled a rotatable shaft 36 which projects upwardly into and through the confines of the cylindrical sleeve 3i and which is journalled in another bearing 35 secured within a flanged enlargement 36 upon the top of the cylindrical sleeve 3|.

Mounted upon the shaft Stia-nd secured thereto, as by means 01- a key 3'5, or any other suitable fastening means, and adapted for rotation therewith is a rotor 39 which is provided with a plural-ity of vanes 56 having downwardly inclined upper edges ii adapted to be juxtaposed to the: inside of the trusts-conical top wall 2! and upwardly inclined lower edges t2 adapted to be juxtaposed to the lrus-tmconieal bottom wall 22. The peripl'ieral, substantially vertical: edges 55- of the vanes are juxtaposed to the annular sidewall 23' ofthe pump housing I i.

Disposed between contiguous vanes ii) of the rotor 3-9 is asegment-sha-p'ed gate t5 which has aperipheral, arcuate edge portion it adapted to be rotated with the rotor 39 in close contiguity tothe annular sidewall 23-01? the pump housing iI. The gate 15 may be formed integrally with the body of the rotor 39 but, in embodiments of my invention where only one gate is mounted upon the rotor, it is desirable to form the gate 65- of a light weight metal such as aluminum and to" mount it between the vanes it of the rotor 3 9 in order to control the imbalance created in the rotor by the weight of the gate located at one side oi the rotor 35". Ihe gate 65, as best shown in Figs. 1 and i, has its peripheral, arouateedge it so dimensioned that the vertical height of the peripheral, arcuate edge Gt, which 5 constitutes the thickness of the gate d5, is less than the vertical height of the peripheral edges 43'- of the contiguous vanes fit; Thus. as best shown in Fig. 1, when the rotor 33 is installed in the pump housing i I, the peripheral, arcuate edge" it of the gate ts is adapted to contact only that portion of the inside of'the' annular side wall 23 which lies substantially above the transverse axis AA of the pump housing I i. Therefore, when the gate 35 is rotated in conjunction withthe rotor 35 through the medium of the shaft 34, which has a pulley t5 secured. to its lower end adapted to be driven from a suitable power source, not shown, it will intermittently obstruct the entry port It and substantially clear theexit port I6 since the segment-shaped gate is r0- ta'ted upon the same plane as that upon which the entry port It is located. The rotor vanes 49 are provided with a plurality of restricted orifices 49 formed therein adjacent the vertical edges 43 of the vanes.

When the pump It is to be utilized in exhausting the air from a suitable vessel, not shown, the intake orifice I9 is connected to' the vessel and a predetermined quantity of mercury, or analogous fluid; having similar characteristics, is poured into the chamber I2 of the pump IIl. Power is then applied to the pulley 49 and the shaft 34 is rotated, the rotation of the shaft 34 causing the concomitant rotation of the rotor 39 and the associated gate 45. If it is desired to forestall the exhausting action of the pump I until the rotor 39 is brought to its maximum efficient speed, the vertical height C of the bottom wall 22 can be so proportioned that the mercury within the housing I I will be rotated in contact with the bottom wall until the rotor has reached a sufficient speed to throw the mercury upward and outward into contact with the annular side wall 23 of the housing I I. The provision of a pump housing II having a frusto-conical top wall 2I and a frustoconical bottom wall 22 serves to permit the rotor 39 to impel the mercury into contact with the inside of the annular side wall 23, thus distributing it in the area where it can be most efficiently utilized in the operation of the pump, as will be described in greater detail below.

As the rotor spins within the housing II, the mercury is distributed between the blades or vanes 49 of the rotor 39 through the medium of the restricted orifices 49, thus preventing the accumulation of a mass of mercury in an area defined by two contiguous blades 49 of the rotor. The equal distribution of the mercury upon the wall 23 of the pump housing I I is thus secured.

The rotation of the rotor 39 causes an annular band of mercury to be distributed in contact with the inside of the annular side wall 23 of the pump housing I I. As the rotor 39 rotates, the gate 45 intermittently closes off the entry port l5 into the surge passage I'I, thereby intermittently preventing the passage of mercury into the surge passage I1. When the gate 45 clears the entry opening to the surge passage I'i, a column of mercury is driven into the surge passage by the action of the vanes 40 of the rotor 39. The column of mercury is driven from the chamber I2 in a direction generally tangential to the path of rotation of the vanes 40 of the rotor 39 and drives before it a column of air which passes into the chamber I2 by means of the exit port I6 from the surge passage H.

A considerable amount of the air is diffused and entrained in the mercury but it is released therefrom as the mercury is driven by the centrifugal action of the rotor 39 into contact with the inside of the annular side wall 23 of the pump housing II and passes out of the pump chamber I2 through the exhaust orifice 26 and its associated exhaust pipe 21. Since the gate 45 is so constructed that its arcuate, peripheral edge portion 46 by-passes the exit port I6 from the surge passage H, the exit into the chamber I2 from the surge passage I1 is never obstructed by the rotation of the gate 45 upon the rotor 39. Since the gate 45 serves to intermittently obstruct the entry port I5 into the surge passage I1 and thus prevents the back flow of exhausted air into the pump chamber I2, and since the column of mercury which is impelled through the surge passage I! by the action of the rotor 39 effectively prevents back flow through the surge passage into the exhaust orifice I9, the necessity for the utilization of a mechanical exhaust valve at the exhaust orifice is eliminated and the pump is able to function effectively without the utilization of such a device.

As can be readily seen from the description of the construction and mode of operation of the above-disclosed embodiment of my invention, a vacuum pump is provided which eliminates the mechanical exhaust valve in vacuum pumpsof the rotary type and effectively prevents back flow of exhausted air by providing a gate associated with the rotor of the pump which effectively seals off the intake orifice of the pump from communication with the pump chamber when the exhaust action is taking place. umn of mercury impelled into the surge passage by the action of the pump rotor serves to prevent back flow from the pump chamber through the surge passage into the intake orifice and the only path which the exhausted air may take is defined by the action of the mercury and it can only take the path of least resistance which is into the pump chamber I2 and therefrom through the exhaust orifice 26.

Another embodiment of my invention is shown in Fig. 2 of the drawings and like numerals of reference are utilized to designate those parts of the embodiment which are identical with similar parts in the previously discussed embodiment of my invention. Since the problems of imbalance created by the utilization of a rotor 39 having one gate formed therein or attached thereto are apt to be rather difficult to overcome by conventional balancing means, I provide in the alternative embodiment of my invention a rotor 39 having vanes 49 which has formed integrally therewith or formed separately therefrom and subsequently fastened thereto a plurality of segment-shaped gates 50 and 5| which are adapted to be rotated upon the rotor 39. The distribution upon the rotor of the gates 50 and SI between contiguous vanes 40 at diametrically opposite sides of the rotor 39 serves to substantially balance the rotor 39 and the balancing problems caused by a rotor having one gate embodied therein are substantially eliminated.

In addition, a vacuum pump embodying a rotor 39 provided with a plurality of oppositely disposed gates 50 and 5| is adapted to provide a more efficient exhausting action, due to the fact that a double action takes place in the exhaustion of a vessel with which the pump is associated, since two exhaustion cycles take place in the same time as consumed by one cycle in a putrnp equipped with a rotor having only a single ga e.

I show in Fig. 3 another embodiment of my invention, in which identical reference numerals are utilized to designate those portions of the pump which are identical with similar portions previously described in the embodiment shown in Fig. 1, which incorporates two surge passages therein adapted to provide a dual action and toy permit the utilization of the pump in exhausting separate vessels simultaneously or in more effectively exhausting a single vessel. The pump 69 is provided with a housing I I constituting a pump chamber I2 in which is mounted a rotor 39 having a plurality of vanes 49 and between two of said vanes 40 is disposed a segment-shaped gate 45 similar in. construction to that previously shown in the embodiment of Fig. l. The housing II has connected at opposite sides thereof or formed integrally therewith a surge passage BI and a surge passage 52. The surge passage Iil has an entry port 53 permittingmercury to be ejected from the pump chamber I2 thereinto and an exit port 64 permitting mercury to be ejected therefrom into the pump chamber I2 while the surge passage 62 has an entry port 65 in communication with the pump chamber I2 and an exit port 66 adapted to communicate with the Further, the colchamber l2. The surge passage BI is provided with an intake orifice El and the surge passage 62 is provided with an intake orifice 6B. When the pump 60 is to be utilized in exhausting one vessel, the intake orifices 61 and 63 can be joined by a suitable fitting to couple their exhausting action in exhausting the one vessel. However, should it be desirable to exhaust two vessels simultaneously, one intake orifice 6'! may be connected to one vessel and the other intake orifice 6-8 may be connected to another vessel. 5

Thus, in the present embodiment of my invention I provide a vacuum pump of the dual action type which may be utilized, in addition, to simultaneously exhaust two vessels. When the rotor 39 is rotated, a band of mercury is distributed about the inside of the side wall 23 of the pump housing H and the gate 55- alternately shuts off the entry opening 63 into the surge passage 6! and the entry opening 65 into the surge passage 62. A column of mercury is injected into the surge passage s: at each rotation of the rotor 39 and a column of mercury is also inject.- ed. into the surge passage 52 at each rotation of the rotor 39.. Thus, a substantially continuous exhausting action can take place if both intake orifices 61 and 58 are. connected to a single vessel or alternate exhausting action will take place if the intake orifices El and 68 are connected to different vessels.

I thus provide by my invention a vacuum pump of the rotary type which dispenseswith the mechanical valve previously utilized to seal off the exhaust orifice associated with prior art pumps and which is more simple in construction andrnore effective in mode of operation than previous rotary type vacuum pumps. In addition, my invention enables me to provide a rotary vacuum pump of the dual action type and also enables me to provide a rotary vacuum pump which is able to simultaneously exhaust two vessels without materially affecting the exhausting action of the pump upon either of the vessels.

While I have shown and described preferred embodiments of my invention, it is obvious that other elements and parts may be substituted for those which have been shown without departing from the spirit of my invention, and I, therefore, do not intend to be limited to the specific forms described but desire to be afforded the full protection of the following claims.

I claim as my invention:

1. In a vacuum pump, the combination of: a housing providing a chamber having an exhaust orifice formed therein; a passage providing an entry port and an exit port communicating with said chamber and an intake orifice adapted to be placed in communication with a vessel to be exhausted; a shaft rotatably mounted in said housing; a rotor mounted upon said shaft for rotation therewith; and a gate secured to said rotor for rotation therewith adapted to intermittently obstruct said entry port to said passage.

In a vacuum pump, the combination of a housing providing a chamber having an exhaust orifice formed therein; a passage providing at one side of said chamber an entry port and an exit port communicating with said chamber and an intake orifice adapted to be'placed in communication with a vessel to be exhausted; a shaft rotatably mounted in said housing; a rotor mounted upon said shaft for rotation therewith; and a gate secured to said rotor for rotation therewith adapted to intermittently obstruct said entry port to said passage.

8 3. In a vacuum pump, the combination of a housing providing a chamber having an exhaust orifice formed therein; a passage providing an entry port and an exit port communicating with said chamber, said entry port being disposed upon a plane above the plane upon which said exit port is disposed, and an intake orifice adapted to be placed in communication with a vessel to be exhausted; a shaft rotatably mounted in said housing; a rotor mounted upon said shaft for rotation therewith; and a gate secured to said rotor for rotation therewith adapted to intermittently obstruct said entry port to said passage.

l. In a vacuum pump, the combination of: a housing providing a chamber having an exhaust orifice formed therein; a passage providing an entry port and an exit port communicating with said chamber and an intake orifice adapted to be placed in communication with a vessel to be exiausted; a shaft rotatably mounted in said housing; a rotor mounted upon said shaft for rotation therewith; and a gate secured to said rotor adapted to be rotated therewith having an arcuate edge portion adapted to intermittently ob- 5.311181 said entry port to said passage and to substantially clear said exit port from said passage. 5. In a vacuum pump, the combination of a housing providing a chamber having an exhaust orifice formed therein; a passage providing an entry port and exit port communicating with said chamber, said entry port being adapted to communicate with said chamber at a point above said exit port, and an intake orifice adapted to be placed in communication with a vessel to be.

- exhausted; a shaft rotatably mounted in said housing; a rotor mounted upon said shaft for rotation therewith; and a gate secured to said rotor for rotation therewith adapted to intermittently obstruct said entry port to said passage.

- 6. In a vacuum pump, the combination of: a housing providing a chamber having an exhaust orifice formed therein; a passage providing an entry port and an exit port communicating with said chamber, said passage being so disposed with reference to the transverse axis of said chamber that one end thereof lies substantially above and one end substantially below said axis, and an intake orifice adapted to be placed in communication with a vessel to be exahusted; a shaft rotatably mounted in said housing; a rotor mounted upon said shaft for rotation therewith; and a gate secured to said rotor for rotation therewith adapted to intermittently obstruct said entry port to said passage.

7. In a vacuum pump, the combination of: a

housing providing a chamber having an exhaust orifice formed therein; a passage providing an entry port and an exit port communicating with said chamber, said passage being so disposed with reference to the transverse axis of said chamber that one end thereof lies substantially above and one end substantially below said axis, and an intake orifice adapted to be placed in communi-- cation with a vessel to be exhausted; a shaft rotatably mounted in said housing; a rotor mount- 4 5; said transverse axis.

8. In a vacuum pump, the combination of: a housing providing a chamber having an exhaust orifice formed therein; a passage providing an entry port and an exit port communicating with said chamber, said entry port being disposed in a plane above said exit port, and an intake orifice adapted to be placed in communication With a vessel to be exhausted; a shaft rotatably mounted in said housing; a rotor mounted upon a shaft for rotation therewith; and a gate secured to said rotor having an arcuate edge portion, the major portion of said arcuate edge portion being disposed on the same plane as said entry port and being adapted upon rotation of said rotor to intermittently obstruct said entry port and to substantially clear said exit port from said passage.

9. In a vacuum pump, the combination of: a housing providing a chamber having an exhaust orifice formed therein; passages providing at either side of said chamber, each of said passages having an entry port and an exit port communicating with said chamber and an intake orifice adapted to be placed in communication with a vessel to be exhausted; a shaft rotatably mounted in said housing; a rotor mounted upon said shaft for rotation therewith; and a gate secured to said rotor for rotation therewith to intermittently obstruct said entry ports to said passages.

10. In a vacuum pump, the combination of: a housing providing a chamber having an exhaust orifice formed therein; a passage providing an entry port and exit port communicating with said chamber and an intake orifice adapted to be placed in communication with a vessel to be exhausted; a shaft rotatably mounted in said housing; a rotor mounted upon said shaft for rotation therewith; and a, plurality of gates secured to said rotor providing for rotation therewith adapted to intermittently obstruct said entry port to said passage.

11. In a vacuum pump, the combination of a housing providing a chamber having an exhaust orifice formed therein; a passage providing an entry port and an exit port communicating with said chamber and an intake orifice juxtaposed to said entry port adapted to be placed in communication with a vessel to be exhausted; a shaft rotatably mounted in said housing; a rotor mounted upon said shaft for rotation therewith; and a gate secured to said rotor for rotation therewith adapted to intermittently obstruct said entry port to said passage.

EVERETT M. HADLEY.

No references cited. 

